Bastian Beranek <bastian.beischer@gmail.com> writes:

> But how to go back? It seems that tab-bar-show should go back to "1" (in
> order to make it a real toggle, i.e. it undoes itself). However, that
> means that after the second toggle-frame-tab-bar the tab-bar will either
> be shown or not, depending on the number of tabs opened at that specific
> time. We have to consider that the user created or closed tabs in
> between, so that means that there will be situations in which
> toggle-frame-tab-bar does not really seem to do anything... For example:
>
> - 1 tab (tab bar hidden)
> - create tab -> 2 tabs (tab bar shown)
> - toggle-frame-tab-bar (tab bar hidden)
> - close tab (tab bar hidden)
> - toggle-frame-tab-bar (tab bar still hidden, because only 1 tab)

I think what we could do is:

a) always toggle the current visibility: That seems to be a must, it
   would be confusing otherwise.

b) The first time toggle-frame-tab-bar is called, add a notice to the
   frame parameters that prevents tab-bar--update-tab-bar-lines from
   changing that frames tab-bar visibility. This means that after the
   toggle the tab-bar visibility keeps its state until
   toggle-frame-tab-bar is called again.

c) When it is called a second time toggle-frame-tab-bar sets the new
   frame parameter to nil and flips the visibility again (see a).

d) Then the tab-bar--update-tab-bar-lines logic will be active again,
   but only after a new tab is created or closed on that frame.

This prevents the problem listed in my last mail, in the last step the
tab-bar will be shown after toggling (although tab-bar-show is 1 and
there is only one tab), but then once you create more tabs or close tabs
it will revert to the usual behavior.

Is this acceptable?

Proposed patch is attached.